SCIENCE Lower Secondary - GoGuru

Perfect GuideLower SecondarySCIENCENotesBook BChristopher N. Prescott(H)PG LSSBNotes TP.indd 11/8/13 9:04 AM

PrefacePERFECT GUIDE TO LOWER SECONDARY SCIENCE NOTES is a study aid for schoolexaminations. With comprehensive notes, this study guide promises to build knowledge andfacilitate understanding for effective learning. These books can be used in conjunction withthe Lower Secondary Science Matters (2nd Edition) textbooks. Textbook links are provided forconvenient referencing and further reading.Features in these books IMPORTANT TERMS AND POINTS are highlighted in bold. These terms are also found inthe Glossary.TRYCHEMISTOPIC2 SEPARATION TEchNIquESNOTES2.1 STUDY ConciseSTUDY NOTES withample illustrationsand photographs.mixturesOMEare found asLEARNING OuTcl substancesthat many usefu.(a) Recognise obtain the pure substanceseparated towhich have tobeoil areter and crudeple air, seawato be separated,res. For examfound as mixtuances which needseawater.and useful substl substances aremon salt) fromvery important Many usefucontain somem chloride (comThesesodiuorres.watermixtuofthe air or purecal propertieslike oxygen fromding on the physimixtures depenods to separateuse different methre. Scientiststs of the mixtuthe constituendsSeparation erchromatographyDistillationEvaporationthey do notcal methods asical change.involve any chemare physiation methods These separd.ance is formeNo new substLinkrs Volume A (2ndScience MatteLower Secondarytechniqueical separationOMEiples of the phys applications of magneticLEARNING OuTcthe basic princof theawareness ofsome examples(b) Show anration and stateof magnetic sepaseparation.is not affectedial from that whichl,ate magnetic mater s like iron or cobalt or nickebe used to separly contains metalattraction canmaterial usual Magneticforce. Magneticby a magneticicsteel.likefrom non-magnetor their alloysls and their alloys ate iron and steelmetaeticto separto pull magnscrap metal yardsnets can be usedis common in Electromagtype of separationmaterial. Thisling.objects for recyc Each LEARNINGOUTCOME isfollowed by studynotes.uesion TechniqTopic 2 Separatout by evaporationfrom the leavesup throughthe xylem tubesYin byosmosis throughthe rootsMovement ofLinkLower SecondaryScience Matters Volume B (2nd Mineral saltsdiffuse into theroothairs in plants.Exam TipBIOLOG TEXTBOOK LINKFor further reading17ore) Private Limitedtional (Singapll Cavendish Interna 2013 Marsha COMMON ERRORRefutes commonmisconceptions.n 4.1Edition) — Sectiowater througha plantEdition) — Section 10.4Common Error As the concentration of mineral salts insideis higher thanthe root hairoutside, diffusion would sendout of the plant.the saltsTherefore plantsn, soand ‘pump’ thehave to use energminerals in bywith a specific functio thatyactive transport.components eachvessels are organsthat has variousthe heart and blooda computer systemmuscleFor example, Just likeDiffusion facilitbody. The heart hasates the movea living organism.blood around thement of gasesspecial jobdoes a ‘system’ inplants. Osmosis(oxygen and carbosystem which pumpscells each with afacilitates theinup the circulatorynabsorption ofitself has differentmakecells are importantwater by the roots. dioxide) andmineral saltsaround. The bloodas the white bloodandbloodout oftissue to pumpinthegas in the blood wherem including heart The human transport systemis called the circuvessels and bloodlatory.BIOLOGYoxygento do. Red cells carry .defence against diseaseLEARNING OUTCOME(d) Identify theparts of the human circulatoryand blood.syste, blood vessesystem. It is madels EXAM TIP Usefulhints for exams.up of the heart, blood The heartis a muscularorgan that pumpCirculatory systemas follows:Hearts blood arounMuscle tissued the body. ThecellpumpingMuscle When theaction isthe multicellularheart musclessystems ensures thatcontract (systole phase), bloodtissues, organs and When theislabour between cells,heart musclesforced out.relax (diastole This division ofly and efficiently.smoothphase), bloodnsfunctiois pulled in. organism 2013 Marshall Cavendish International (Singapore) Private Limitedmuscle cell etc. Thisexample nerve cell,smallercertain tasks, forthe workload intoised in carrying outcy as it breaks downlevel increases efficienExam TipCells become specialTopic 8 Transpoon a cellularrt Systemof labourdivisionIn Living Thingsand more specifictasks.73OF TERMS7.2 GLOSSARYThe tiny basic unitone or more cells.CellCell membraneCell sapCell wallCelluloseChlorophyllChloroplast 2013 Marshallof living material.All living organismsare made up ofwhich allowsaround the celleable outer skinA thin partially-permthrough.substances to diffusewater andIt contains mainlye of a plant cell.vacuoltheinLiquid foundand minerals.dissolved sugarscell.plantost layer of aA thick, rigid outermthe cell wallplants which makesin the cell wall ofThe substance foundrigid.the sun tos light energy fromin plants which absorbA pigment foundis process.start the photosynthescontainsof the plant cell whichin the cytoplasmelle)(organreThe structuchlorophyll.nal (Singapore) PrivateCavendish InternatioLimitedBasic UnitTopic 7 Cell: TheOf Life67 GLOSSARY OFTERMS at theend of everychapter providesexplanations tovarious scientificterms.iii02 (S)PGLSSBKB(2nd Ed) Prelims.indd 312/30/12 2:41 PM

ContentsCHEMISTRYTopic 1: Chemical Composition of MatterTopic 2: Separation Techniques22Topic 3: The Particulate Nature of Matter34Topic 4: Atoms and Molecules45Topic 5: Chemical Changes54Topic 6: Diversity of Living Things76Topic 7: Cell: The Basic Unit of Life90Topic 8: Transport System in Living Things100Topic 9: Digestion in Human Beings115Topic 10: Human Sexual Reproduction System127Topic 11: Ecosystems1481BIOLOGYiv02 (S)PGLSSBKB(2nd Ed) Prelims.indd 412/30/12 2:41 PM

CHEMISTRYTOPIC1.1STUDY NOTESLEARNING OUTCOME(a) State that elements are the building blocks of living and non-living matter andrecognise if a substance is an element. All living and non-living matter matter consist of basic units called elements. Scientists havediscovered about 116 elements of which 92 occur naturally on Earth. An element is a substance which cannot be broken down into two or more simpler substancesby chemical means. Some elements occur uncombined on Earth. Examples of these elements are gold and silverin the ground or nitrogen and oxygen in the air. Most elements occur combined with other elements. For example, the element hydrogenmainly occurs combined with the element oxygen in the form of water. Most metallic elementscombine with oxygen or sulphur to form ores or minerals.Galena, which is a lead ore, contains lead chemically combined with sulphurExperiment Is water an element?oxygen gashydrogen gaswater acidified with dilutesulphuric acidcarbon electrode6V batteryElectrolysis of water: Water Oxygen Hydrogen 2013 Marshall Cavendish International (Singapore) Private Limited03 (S)PGLSSBKB(2nd Ed) 01.indd 1Topic 1112/30/12 2:42 PM

How can you tell if water is an element? Remember that by definition, an element cannot bebroken down into two or more simpler substances. However, if we pass electricity throughwater, it is broken down into its constituent elements hydrogen and oxygen. The water hasto be acidified with a little acid since pure water is a poor conductor of electricity. Thisdecomposition of a substance by passage of electricity is called electrolysis. The most abundant element in the air is nitrogen, which makes up 78% of air. This is followedby oxygen which makes up 21% of air. In the Earth’s crust, the two most abundant elementsare oxygen (about 47%) and silicon (about 28%).LinkLower Secondary Science Matters Volume A (2nd Edition) — Section 3.1Exam TipElements contain only one type of atom whereas compounds and mixtures always contain more thanone type of atom.LEARNING OUTCOME(b) Recognise that the Periodic Table is an organised chart of all the elements. All known elements are arranged in a chart called the Periodic Table.A group is a verticalcolumn of elements.non-metalsHLiBemetalsNa ArMn FeCoNiCuZn Ga Ge AsSeBrKrNb MoTcRuRhPdAgCdInSn SbTeIXeTaReOsIrPtAu HgTIPdPoAtRnWBiA period is ahorizontal rowof elements. more than 30 other elementsThe Periodic Table Every element is represented by a chemical symbol. For example, oxygen is represented by Oand hydrogen by H. Each vertical column in the Periodic Table is called a group. Elements within a group havesimilar chemical properties. Each horizontal row in the Periodic Table is called a period. The elements, as we go from leftto right across the period, change from solid metals to liquid or gaseous non-metals.2Topic 103 (S)PGLSSBKB(2nd Ed) 01.indd 2 2013 Marshall Cavendish International (Singapore) Private Limited12/30/12 2:42 PM

CHEMISTRY The ‘zigzag staircase’ line going across the Periodic Table separates metals and non-metals.Below the ‘staircase line’ on the left hand side are the metals. Above the ‘staircase line’ on theright hand side are the non-metals. The elements near the zigzag line are called metalloids.These elements have the properties of both metals and non-metals.Aluminium foilSilicon ingotsArgon gasExam TipThe Periodic Table is a list of elements in order of increasing atomic size. Vertical columns are calledgroups and elements within a group have similar chemical properties. Horizontal rows are calledperiods and across a period from left to right the elements change from metal to non-metal.LEARNING OUTCOME(c) Recognise that elements are classified into metals and non-metals according totheir properties. Elements in the Periodic Table can be classified into metals and non-metals according to theirdifferent physical properties.MetalsNon-metals Good conductor of heat Poor conductor of heat Good electrical conductors Poor electrical conductors Can be pulled into wires (ductile) Non-ductile Can be beaten into shape (malleable) Brittle and snap easily Give a ringing sound (sonorous) Not sonorous Shiny to look at (lustrous) Dull appearance High densities Low densities 2013 Marshall Cavendish International (Singapore) Private Limited03 (S)PGLSSBKB(2nd Ed) 01.indd 3Topic 1312/30/12 2:42 PM

The most common metals in the Earth’s crust are aluminium and iron. The most abundantnon-metals in the Earth’s crust are oxygen and carbon.NameChemical SymbolAppearanceMetalsAluminiumAlSilvery solidCopperCuReddish-brown solidIronFeGrey solidMagnesiumMgSilvery solidMercuryHgSilvery liquidZincZnGreyish solidNon-MetalsCarbonCBlack solidHydrogenHColourless gasIodineIBlack solidNitrogenNColourless gasOxygenOColourless gasSulphurSYellow solid Some uses of common metals and non-metals are shown in the following tables.Metal4UsesAluminiumKitchen foil, aircraft construction, drink cans, window framesCopperWater pipes, electrical wires, brass and bronze alloysIronConstruction work, engine blocks, gates, steel alloysMagnesiumFireworks, medicines (Epsom salts)MercuryFluorescent lamps, thermometers, dental fillingsZincGalvanised roofs, casing of dry cells, brass pins of plugsTopic 103 (S)PGLSSBKB(2nd Ed) 01.indd 4 2013 Marshall Cavendish International (Singapore) Private Limited12/30/12 2:42 PM

PERFECT GUIDE TO LOWER SECONDARY SCIENCE NOTES is a study aid for school examinations. With comprehensive notes, this study guide promises to build knowledge and facilitate understanding for effective learning. These books can be used in conjunction with the Lower Secondary Science Matters